The PFL 2 mixed martial arts event for the 2018 season of the Professional Fighters League was held on June 21, 2018, at the Chicago Theatre in Chicago, Illinois. It was the second regular season event of 2018 and included only fights in the lightweight and light heavyweight divisions.

KOTC 37: Unfinished Business was an event held on June 12, 2004 at the Soboba Casino in San Jacinto, California, United States.

UFC 103: Franklin vs. Belfort was a mixed martial arts event held by the Ultimate Fighting Championship (UFC) on September 19, 2009 in Dallas at the American Airlines Center.

UFC 106: Ortiz vs. Griffin 2 was a mixed martial arts event held by the Ultimate Fighting Championship (UFC) on November 21, 2009 at the Mandalay Bay Events Center.

UFC 110: Nogueira vs. Velasquez was a mixed martial arts event held by the Ultimate Fighting Championship (UFC) on Sunday, 21 February 2010 in Sydney, New South Wales, Australia, at Acer Arena.

UFC Fight Night 22: Marquardt vs. Palhares was a mixed martial arts event held by the Ultimate Fighting Championship on September 15, 2010 at the Frank Erwin Center in Austin, Texas. The event also served as a lead in to the season premiere of The Ultimate Fighter: Team GSP vs. Team Koscheck.

UFC 123: Rampage vs. Machida was a mixed martial arts event held by the Ultimate Fighting Championship on November 20, 2010 at the Palace of Auburn Hills in Auburn Hills, Michigan.